I actually ordered a 63mm, but there were none available. Anyway, close enough

I know many if not most fibers come with 100-110mm lenses, I wanted a 150 for the extra working area. Then I got my 220, which is closer to 250, the thing will engrave 11" diagonally. Not a lot of vertical space available, but I was able to run 1" high characters across 11" when I checked it...

So I got a new customer via an old customer, gobs of work, small parts by the hundreds, all fiber. But some require deep engraving. The new customer proper has a 20w fiber, and they did a test engraving they were okay with and share the settings. Pretty much the same settings I would've used, but I cut back a bit to account for my 30 watts. They okayed my first article. Best I could muster was 3 minutes 18 seconds...

I ordered this new lens the minute I got the parts, did the proof with the 150 lens.

When the 72 showed up, first thing was to find it's focus distance-- 4.78". Second thing was to find a crate so I could get the parts close enough!

Third was some test engraving. I found out what Tim went thru with his 50 watter - I used the same settings I'd normally use, and it literally left melted goo inside the letters, the result of the much smaller focus spot and the resulting increase in power density - in my lens research lately, I found that a 50% decrease in beam spot size will increase power density 200%--!

Seems it's true, as the beam spot is VERY noticeably smaller, so much so vs the 150 that I had to cut my hatch spacing almost in half. And I also had to add .0015" to my project's text and logo outlines to get the same finished cut width as I got with the 150 lens...

But even with doubling the hatch (adds work time) and fattening the work (more added time), I was still able to increase my cutting speed by 5x (actually I NEEDED to), and reduce the passes from 12 to 9. in the end, I'm probably a snick deeper than my first article, and a 9x3 hatch pass run only takes 1:17 ! 77 seconds vs 198 seconds with the 150 lens... THAT is huge, especially when running hundreds of parts!

The caveat of course is the work area is less than 3" square, but none of these parts are that big!

I knew a smaller lens would help, but nearly 3x faster I wasn't expecting!

This is why I'm in need of a 50 watt machine. Not only will I have nearly the same power with a 150 lens, I'll have the wider beam spot which may speed up the engraving even more. Plus I need the extra work area. And with the 220 lens, I get even more work area, and I should have about the same usable power as 30w gives me with the 150 lens. Another reason: right now-Sunday afternoon- I have jobs running on 10 machines, and the fiber has about 4 days worth of work already backed up, with more always coming in...

I'm supposed to (semi-) retire next summer, and I have more work piling up than ever...

anyway, if any of you have fancied getting a small factor lens for your fiber, especially if you're engraving AR lowers, I highly recommend one! Mine was $103 on Ebay...